1. Field of the Invention
The present invention is directed to sheet bundle stowage in an image reproduction apparatus, and more particularly, it relates to a mechanism for handling bundled stacks of copy sheets withdrawn from sorting trays of a sorting device associated with a copying machine, and for guiding the bundles into a stowing bin.
2. Description of Related Art
Photocopying machines and like image-reproducing apparatus can be provided with sheet sorters for sorting image-bearing copy sheets following the image-reproducing operation. Copy sheet-sorting devices in image-reproducing applications that moreover feature a stapler for stapling the sheets once they have been sorted into copy stacks are commercially available.
Copy sheet sorting devices for copying machines are provided with a set of sorting trays, and the number of sorting trays used in a given copying operation will correspond to the number of document copies designated by an operator. With copying machines equipped with an automatic sheet feeder capable of recirculating a stack of original document sheets over the image-scanning station, it is possible to produce a number of copies of a document stack greater than the number of trays furnished in the sorting device by passing the same copying operation through a number of cycles. This makes it necessary, however, to remove the sorted copy-sheet stacks from the trays, to allow copy sheets from the next copying cycle to be properly sorted into temporary storage in the tray set. This in turn requires that the sheet stacks be bundled (typically they are stapled), if they are to be removed by other than manual means. Thereafter, the bundled copy-sheet stacks may be discharged into a stowing bin or the like, apart from the sorting trays of the sorting device.
In one known sorting device for such an application, copy-sheet stacks are transported to a stapling section where the sheets in the stack are held momentarily, brought into register, and then the stack is stapled. The stapler in this device is located below the sorting trays, and a stowing bin is provided beneath the stapler for receiving the copy-sheet bundles.
Copy-sheet bundles thus processed by the sorting device accompanying the copying machine are left stowed to the side of the copying machine, beneath the sorting trays in a position encumbering removal. Accordingly, in a co-pending application (U.S. application Ser. No. 08/053,952, filed Apr. 28, 1993), the present applicant has disclosed a copy-sheet bundle stowing unit on the front of a sorting device for an associated copying machine. The sheet-bundle stowing unit discharges sorted and stapled copy-sheet bundles into stowage in a forward-opening stowing bin, in front of the sorting trays beside the copying machine. The bundled copy-sheet stacks are therein easily removed from the stowing bin of the sorting device.
In the bundle stowing unit attached to the sorting device accordingly proposed by the applicant earlier, the sorting trays, lying in the direction of sheet-sorting transport as the copy sheets are discharged from the photocopying machine, are inclined upward. Stapled copy-sheet stacks are withdrawn forward from the inclined trays, transverse to the direction of copying machine sheet discharge, into a stowing path of the stowing unit. The stowing path includes a bundle-receiving surface, a bottom front portion of which is horizontal, lying in the stowing bin, while the remaining portion is inclined upward and away (i.e., toward the sorting trays). As the copy sheet bundle is stowed, the inclined bundle drops onto the bundle-receiving surface. Therein, the weight of the bundle is initially on that corner lying front and downward as it strikes the bundle-receiving surface, and the bundle corner consequently can become bent or crumpled. This can particularly be a problem in cases where the copy bundles are stacks of sheets of multiple sizes.
In the sheet-bundle stowing unit as disclosed in U.S. application Ser. No. 08/053,952, the bundles should land face-up on the inclined bundle-receiving surface, flexed slightly with the (usually) lengthwise forward portion lying lower than the lengthwise rearward portion. Accordingly, when the stowing bin is drawn open, the copy-sheet bundles are properly presented. In this configuration, however, occasionally the bundles dropping onto the receiving surface do not land correctly, sometimes bending or crumpling, or, moreover, turning upside down, for example, or being left leaning against a front wall of the stowing bin. Consequently disarranged, the stack of copy-sheet bundles is not easily removed from the stowing bin.
To address such problems in the system as above for discharging and dropping copy-sheet bundles into a stowing bin, the present applicant has further disclosed, in Japanese Patent Application Laid-Open No. 64429/1993, a sorting device having a bundle-stacking apparatus for discharging copy-sheet bundles into a bundle-stowing bin that is provided with a bundle-receiving surface lying at an incline generally corresponding to the inclination of the sorting trays. While the bundle-stacking apparatus is situated in front of the sorting device, access to the bundle-stowing bin in order to remove the finished and stowed copy-sheet bundles is lateral.
A copy-sheet bundle discharge/stowing path is defined in the bundle-stacking apparatus between the sorting trays and the stowing bin. The discharge/stowing path includes a standing guide wall lying inclined, wherein it is generally orthogonal to both the angle of incline of the sorting trays, and of the bundle-receiving surface lying parallel below. Accordingly, the standing wall serves to conduct endwise each bundle transversely discharged from a sorting tray, such that the bottom of the bundle will land at once on the bundle-receiving surface, preventing bending or crumpling damage to the bundle.
In this bundle-stacking apparatus, however, there is a tendency for discharged bundles dropping along the standing wall into stowage to flex against the standing wall under their own weight, especially if there are fewer sheets in the bundles, or if the sheets are not very stiff. This tendency of the bundles to flex leads to problems in how the bundles land on the bundle-receiving surface, such that they might nonetheless become bent or crumpled. Poorly stowed bundles, moreover, can be a nuisance to remove from the stowing bin.